This disclosure relates to an apparatus used during thermal spray operations, and, more particularly, to an apparatus for the continuous and stable delivery, atomization, and injection of solution for producing films, coatings, or bulk forms in a solution thermal spray process such that the desired microstructural features of the films, coatings, or bulk forms are obtained upon application. The invention also particularly relates to the control of the temperature of the substrate at which the films, coatings, or bulk forms are formed or deposited.
In thermal spray processes, particles of metallic, composite, or ceramic materials are at least partially melted, accelerated, and impinged onto a target substrate to produce a coating having anti-corrosion, anti-wear, thermal insulation or other functional properties. The coating is thickened and built up through the continuous overlaying of material in the form of droplets to produce a coating having splat/lamellar boundary features and partially melted and/or unmelted particle inclusions. The lamellar structure of such coatings, because of their low tolerance to thermal stress induced during thermal cycling in the service environment, may be considered a disadvantage for certain applications, particularly in thermal barrier coating (TBC) applications.
Although the deposited coatings typically derive from solid material, liquid precursors comprising aqueous solutions of metal salts, metal-organic salt solutions, or polymer-based solutions may also be utilized as feedstock sources to produce coatings, particularly when the thermal spray process is a plasma spray process.
The above discussed and other features will be appreciated and understood by those skilled in the art from the following detailed description and drawings.